Dead PCM?
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Joined: Jun 2020
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From: Michigan
on the relay is says pin85 is slot 1 in the PDC and slot 1 has a green and black wire going to it under the PDC
when I put the lead into slot 1 aka pin85 and the other lead to a2 I get a reading of .3 ohms
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Well yes and no. Pin A2 switched ignition power comes from the same source as the power at the fuel pump relay, hence the same wire colors. You'll find the same colors at the ASD relay as well. But this is merely the power supply and there is no control between the relay and the PCM via that connection. Control is on the other side (brown/white) which the PCM switches to ground to activate the fuel pump. Let's circle back and establish for good if the brown/white wiring is good between the relay and the PCM. I think that has not been proven yet.
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From: Clayton MI
Thread Starter
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Professional
Joined: Jun 2020
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From: Michigan
Well yes and no. Pin A2 switched ignition power comes from the same source as the power at the fuel pump relay, hence the same wire colors. You'll find the same colors at the ASD relay as well. But this is merely the power supply and there is no control between the relay and the PCM via that connection. Control is on the other side (brown/white) which the PCM switches to ground to activate the fuel pump. Let's circle back and establish for good if the brown/white wiring is good between the relay and the PCM. I think that has not been proven yet.
my multimeter beeps for continuity and shows infinite resistance which is .3ohms on mine all the way from the pdc pin86 brown and white to the pin19 at the pcm..
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Professional
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From: Michigan
the green black wire from my pdc pin85 shows .3ohms at the a2 pin at my pcm
the brown and white wire from pin86 at my pdc shows .3 ohms at pin 19 at the pcm...
both Beep for continuity and my multimeter shows .3ohms when touching the leads together and when testing on a single piece of known good wire...
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Joined: Apr 2010
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From: Clayton MI
Infinite resistance is an open circuit. On your meter, .3 ohms is actually zero. (no resistance) The wire itself is good, but, if you are getting a reading of anything other than infinite when testing from various points to ground on that wire, there's a short somewhere. If you only have something like 9 ohms from pin 85 (on my wiring diagram..... this is the pcm side of the circuit, the brown/white wire) to ground, theres a short there. Need to find it.
Thread Starter
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Professional
Joined: Jun 2020
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From: Michigan
Infinite resistance is an open circuit. On your meter, .3 ohms is actually zero. (no resistance) The wire itself is good, but, if you are getting a reading of anything other than infinite when testing from various points to ground on that wire, there's a short somewhere. If you only have something like 9 ohms from pin 85 (on my wiring diagram..... this is the pcm side of the circuit, the brown/white wire) to ground, theres a short there. Need to find it.
i guess I’m just confused as heck as to where I’m supposed to be looking for a short. I’ve traced both the green and black wire and the brown white wire more times than I can count now end to end and can’t find anything..
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oh okay I’m still learning a lot I guess I’m sorry.
i guess I’m just confused as heck as to where I’m supposed to be looking for a short. I’ve traced both the green and black wire and the brown white wire more times than I can count now end to end and can’t find anything..
i guess I’m just confused as heck as to where I’m supposed to be looking for a short. I’ve traced both the green and black wire and the brown white wire more times than I can count now end to end and can’t find anything..